The present invention relates generally to a backup plate assembly for grinding systems, preferably a backup plate assembly for use in a grinding system which allows observation of a work surface during operation of the grinding system.
High-speed grinders are used for many different applications for abrading a work surface. Typical rotary grinders include a rotatable shaft extending from the grinder. An abrasive disc attached to a backup plate is mounted on an end of the rotatable shaft. Typical grinding operations include positioning the grinding system at an angle relative to the work surface during operation of the grinding system. The grinder is held at an angle, such that the rotatable shaft is angled relative to a plane of the work surface. Typical grinding angles range from about 5xc2x0 to 45xc2x0. An outer edge of the abrasive disc and backup plate assembly is pressed against the work surface while the grinder is operated. The result is an abrading of the work surface by the abrasive article.
During operation of the grinder system on a work surface it is desirable to view the abraded portion of the work surface. Typically, this is accomplished by abrading the work surface, moving the grinder system to view the abraded portion of the work surface, and repositioning the grinder system at the abraded portion of the work surface. This routine is repeated until grinding is complete.
Modifications have been made to the abrasive disc and backup plate assembly in order to view the abraded work surface during operation of the grinder system (see, for example, U.S. Pat. No. 6,007,415 (Van Osenbruggen)). Known abrasive disc and backup plate assembly designs include circular openings or apertures in a sanding disc and corresponding circular openings or apertures in the backup plate. When rotated at a high speed during operation of the grinder system, the abraded work surface is viewable through the apertures in the sanding disc and apertures in the backup plate. This type of sanding disc and backup plate assembly requires that the openings in the sanding disc be designed to match with the openings in the backup plate. The openings in the sanding disc must be registered and aligned with the openings in the backup plate, and such registration must be maintained while mounting the sanding disc and backup plate assembly on the grinder system rotatable shaft.
Other abrasive disc and backup pad assemblies include portions or regions removed from the outside perimeters of the abrasive disc and backup plate to enable viewing of an abraded work surface during operation of a grinder system (see, for example, U.S. Pat. No. 6,062,965 (Knowlton)). Again, the removed regions about the outer perimeters of the sanding disc must correspond to the removed regions about the outer perimeter of the backup plate. The sanding disc removed regions must be registered and aligned to the removed regions of the backup plate and secured to the rotatable shaft of the grinder system. Another known grinding disc is disclosed having both apertures extending through the disc surface and removed regions spaced about the outer circumference of the grinding disc (see, for example, U.S. Pat. No. 6,077,156 (Amin et al.)).
It is also known to provide openings or apertures in a grinder backup plate as part of a dust control system. The dust control system includes a shroud placed over the openings in the backup plate and is connected to a vacuum source. During operation of the grinder, dust, dirt, and abraded material (termed xe2x80x9cswarfxe2x80x9d) is removed through the apertures and shroud via the vacuum system (see, for example, U.S. Pat. No. 4,932,163 (Chilton et al.)).
Other known systems have been designed to aid in cooling of the abrasive disc during grinder operation, thereby extending the useful life of the abrasive disc. For example, one known design includes, a plurality of ribs extending from a surface of the backup plate. The ribs extending from a surface of the backup plate provide both channels for removal of xe2x80x9cswarfxe2x80x9d or other undesirable materials during operation of the grinder system while providing a cooling effect to the grinding disc.
The present invention relates generally to an abrasive article backup plate assembly for grinding systems, preferably an abrasive article backup plate assembly for use in a grinding system which allows observation of an abraded surface during operation of the grinding system and grinding systems employing such assemblies.
In one embodiment, the present invention provides an abrasive article backup plate assembly. The abrasive article backup plate assembly includes an abrasive article having an abrasive surface that includes a viewing window (preferably, two or more viewing windows) within the abrasive surface. A support member is provided which includes a first major surface which supports the abrasive article. At least a portion of the support member is made of material sufficiently clear to collectively see through the support member and the viewing window. For embodiments in which the assembly rotates during use, preferably at least a portion of the support member is made of material sufficiently clear to allow observation of a work surface collectively through the support member and the viewing window during rotation of the assembly about an axis substantially perpendicular to the first major surface.
In another embodiment, the present invention provides an abrasive article backup plate assembly. The abrasive article backup plate assembly includes an abrasive article having an abrasive surface having an average diameter. A portion of the abrasive surface projects beyond the average diameter such that there is a first viewing area between a first two adjacent portions of the abrasive surface that project beyond the average diameter of the abrasive surface. A support member is provided including a first major surface which supports the abrasive article. A portion of the support member is made of material sufficiently clear to collectively see through the support member and the abrasive article viewing area. For embodiments in which the assembly rotates during use, preferably at least a portion of the support member is made of material sufficiently clear to allow observation of a work surface collectively through the support member and the viewing window during rotation of the assembly about an axis substantially perpendicular to the first major surface. Optionally, the abrasive article includes two or more viewing areas. Optionally, the viewing area(s) is a viewing window(s). In another aspect, the abrasive article includes a viewing window(s) in addition to the viewing area(s).
In another embodiment, the present invention provides a grinder system. The grinder system includes a grinder having a shaft (typically, longitudinally extending shaft) and an abrasive article backup plate assembly according to the present invention attached thereto. Typically, a hub system is attached to the support member, wherein the hub system is connectable to the longitudinally extending shaft.
The present invention also provides a method of abrading a surface utilizing an abrasive article backup plate assembly according to the present invention. At least a portion of the abrasive of the abrasive article backup plate assembly may be contacted with a substrate surface to be abraded, and at least one of the abrasive article backup plate assembly or substrate surface may be moved relative to the other. For example, the abrasive article backup plate assembly may be rotated about an axis.
The abrasive article backup plate assembly according to the present invention includes a support member made of materials sufficiently clear to allow observation through the support member, and as such does not require registration or alignment with viewing windows or viewing areas of an abrasive article prior to mounting the abrasive article backup plate assembly onto a grinder system. The clear backup plate can be universally used with many different shapes and configurations of abrasive articles.